IOTA/IOTA-ES occultation update for (840) Zenobia / HIP 41900 event on 2012 Oct 24, 02:56 UT Visible from Africa Summary ------- On 2012 Oct 24 UT, the 24 km diameter asteroid (840) Zenobia will occult a 8.0 mag star in the constellation Cancer for observers along a path across Africa. In the case of an occultation, the combined light of the asteroid and the star will drop by 7.5 mag to 15.5 mag (the magnitude of the asteroid) for at most 1.4 seconds. This update is based on UNSO/Flagstaff astrometry for the asteroid kindly provided by Hugh Harris, historical astrometry from the MPC files (via AstDys), and the following catalogs for the star position: . The event at a glimpse ---------------------- * Rank: 26 * date and approx. time of event: 2012 Oct 24, 02:50 - 2012 Oct 24, 02:56 UT * geocentric midpoint of event [JD]: 2456224.62287083 * magnitude of target star: 8.0 * magnitude drop [mag]: 7.5 * estimated maximum duration [s]: 1.4 * Moon: 71 % sunlit, 160° distance * Sun: 84° distance * rough path description: Africa The occultation path -------------------- * approximate projected width [km]: 24 * 1 sigma uncertainty interval [path widths]: +/- 2.62 * 1 sigma uncertainty interval [seconds]: +/- 3.8 * 1 sigma uncertainty interval approx RA,DE ["]: (+/- .028 +/- .026) * 1 sigma uncertainty ellipse (major, minor, PA): ( .028", .026", 101° ) * approx speed of asteroid's shadow [km/s]: 17.3861 * website for maps: http://www.asteroidoccultation.com Path Coordinates: Occultation of HIP 41900 by 840 Zenobia on 2012 Oct 24 Centre Star Star Sun Path Limits Error Limits E. Longitude Latitude U.T. Alt Az Alt Limit 1 Limit 2 Limit 3 Limit 4 o ' " o ' " h m s o o o o ' " o ' " o ' " o ' " Latitude Latitude Latitude Latitude - 41 0 0 15 49 48 2 50 58 1 74 -83 15 42 55 15 56 40 15 6 48 16 32 41 - 40 0 0 16 6 7 2 50 58 2 74 -82 15 59 15 16 12 59 15 23 14 16 48 55 - 39 0 0 16 21 55 2 50 58 3 74 -81 16 15 4 16 28 46 15 39 7 17 4 37 - 38 0 0 16 37 11 2 50 59 4 75 -80 16 30 21 16 44 2 15 54 29 17 19 48 - 37 0 0 16 51 56 2 50 59 5 75 -79 16 45 7 16 58 45 16 9 19 17 34 27 - 36 0 0 17 6 9 2 51 0 6 75 -78 16 59 21 17 12 58 16 23 37 17 48 35 - 35 0 0 17 19 51 2 51 1 7 76 -77 17 13 3 17 26 38 16 37 24 18 2 11 - 34 0 0 17 33 0 2 51 1 8 76 -76 17 26 13 17 39 47 16 50 38 18 15 16 - 33 0 0 17 45 38 2 51 2 9 76 -75 17 38 52 17 52 24 17 3 21 18 27 49 - 32 0 0 17 57 44 2 51 3 10 77 -75 17 50 59 18 4 30 17 15 32 18 39 51 - 31 0 0 18 9 19 2 51 4 11 77 -74 18 2 34 18 16 3 17 27 10 18 51 21 - 30 0 0 18 20 21 2 51 6 12 77 -73 18 13 37 18 27 5 17 38 17 19 2 20 - 29 0 0 18 30 52 2 51 7 13 77 -72 18 24 9 18 37 36 17 48 52 19 12 46 - 28 0 0 18 40 52 2 51 8 14 78 -71 18 34 9 18 47 34 17 58 55 19 22 42 - 27 0 0 18 50 19 2 51 10 15 78 -70 18 43 37 18 57 1 18 8 26 19 32 6 - 26 0 0 18 59 15 2 51 12 15 78 -69 18 52 33 19 5 56 18 17 25 19 40 58 - 25 0 0 19 7 38 2 51 13 16 79 -68 19 0 57 19 14 19 18 25 52 19 49 18 - 24 0 0 19 15 31 2 51 15 17 79 -67 19 8 50 19 22 11 18 33 48 19 57 8 - 23 0 0 19 22 51 2 51 17 18 79 -66 19 16 11 19 29 31 18 41 11 20 4 25 - 22 0 0 19 29 40 2 51 19 19 80 -65 19 23 0 19 36 19 18 48 2 20 11 11 - 21 0 0 19 35 56 2 51 21 20 80 -64 19 29 17 19 42 36 18 54 21 20 17 26 - 20 0 0 19 41 42 2 51 23 21 80 -63 19 35 3 19 48 21 19 0 9 20 23 8 - 19 0 0 19 46 55 2 51 26 22 81 -62 19 40 16 19 53 34 19 5 24 20 28 20 - 18 0 0 19 51 37 2 51 28 23 81 -61 19 44 58 19 58 15 19 10 8 20 33 0 - 17 0 0 19 55 46 2 51 31 24 81 -60 19 49 8 20 2 25 19 14 19 20 37 8 - 16 0 0 19 59 25 2 51 33 25 81 -59 19 52 47 20 6 2 19 17 59 20 40 45 - 15 0 0 20 2 31 2 51 36 26 82 -58 19 55 53 20 9 8 19 21 6 20 43 50 - 14 0 0 20 5 5 2 51 39 27 82 -57 19 58 28 20 11 43 19 23 42 20 46 23 - 13 0 0 20 7 8 2 51 41 28 82 -56 20 0 30 20 13 45 19 25 45 20 48 25 - 12 0 0 20 8 39 2 51 44 29 83 -56 20 2 1 20 15 16 19 27 16 20 49 55 - 11 0 0 20 9 38 2 51 47 30 83 -55 20 3 0 20 16 15 19 28 16 20 50 54 - 10 0 0 20 10 5 2 51 51 31 83 -54 20 3 28 20 16 42 19 28 43 20 51 21 - 9 0 0 20 10 0 2 51 54 32 83 -53 20 3 23 20 16 37 19 28 38 20 51 16 - 8 0 0 20 9 23 2 51 57 33 84 -52 20 2 46 20 16 0 19 28 1 20 50 40 - 7 0 0 20 8 14 2 52 0 34 84 -51 20 1 37 20 14 52 19 26 51 20 49 32 - 6 0 0 20 6 33 2 52 4 34 84 -50 19 59 56 20 13 11 19 25 10 20 47 51 - 5 0 0 20 4 20 2 52 7 35 85 -49 19 57 43 20 10 58 19 22 56 20 45 39 - 4 0 0 20 1 35 2 52 11 36 85 -48 19 54 57 20 8 13 19 20 9 20 42 56 - 3 0 0 19 58 18 2 52 15 37 85 -47 19 51 40 20 4 56 19 16 50 20 39 40 - 2 0 0 19 54 29 2 52 19 38 85 -46 19 47 50 20 1 7 19 12 59 20 35 52 - 1 0 0 19 50 7 2 52 23 39 86 -45 19 43 28 19 56 45 19 8 35 20 31 32 0 0 0 19 45 12 2 52 27 40 86 -44 19 38 33 19 51 51 19 3 39 20 26 40 1 0 0 19 39 46 2 52 31 41 86 -43 19 33 6 19 46 25 18 58 10 20 21 15 2 0 0 19 33 46 2 52 35 42 86 -42 19 27 7 19 40 26 18 52 8 20 15 19 3 0 0 19 27 15 2 52 39 43 86 -41 19 20 34 19 33 55 18 45 34 20 8 50 4 0 0 19 20 10 2 52 43 44 86 -40 19 13 29 19 26 51 18 38 26 20 1 48 5 0 0 19 12 33 2 52 48 45 87 -39 19 5 52 19 19 14 18 30 46 19 54 14 6 0 0 19 4 23 2 52 52 46 87 -38 18 57 41 19 11 5 18 22 32 19 46 8 7 0 0 18 55 40 2 52 57 47 87 -37 18 48 58 19 2 23 18 13 46 19 37 28 8 0 0 18 46 24 2 53 2 48 87 -36 18 39 41 18 53 7 18 4 26 19 28 16 9 0 0 18 36 36 2 53 6 49 87 -36 18 29 52 18 43 19 17 54 33 19 18 32 10 0 0 18 26 14 2 53 11 50 87 -35 18 19 29 18 32 58 17 44 7 19 8 14 11 0 0 18 15 18 2 53 16 51 87 -34 18 8 33 18 22 3 17 33 7 18 57 23 12 0 0 18 3 50 2 53 21 52 87 -33 17 57 4 18 10 36 17 21 34 18 45 59 13 0 0 17 51 48 2 53 26 53 87 -32 17 45 1 17 58 35 17 9 27 18 34 2 14 0 0 17 39 13 2 53 32 54 87 -31 17 32 25 17 46 0 16 56 47 18 21 32 15 0 0 17 26 4 2 53 37 54 87 -30 17 19 16 17 32 52 16 43 33 18 8 29 16 0 0 17 12 22 2 53 42 55 87 -29 17 5 32 17 19 11 16 29 45 17 54 52 17 0 0 16 58 6 2 53 48 56 87 -28 16 51 16 17 4 56 16 15 23 17 40 42 18 0 0 16 43 16 2 53 53 57 87 -27 16 36 25 16 50 7 16 0 28 17 25 58 19 0 0 16 27 53 2 53 59 58 87 -26 16 21 1 16 34 45 15 44 58 17 10 41 20 0 0 16 11 56 2 54 4 59 86 -25 16 5 3 16 18 49 15 28 55 16 54 50 21 0 0 15 55 25 2 54 10 60 86 -24 15 48 31 16 2 19 15 12 18 16 38 25 22 0 0 15 38 20 2 54 16 61 86 -23 15 31 25 15 45 15 14 55 6 16 21 27 23 0 0 15 20 41 2 54 22 62 85 -22 15 13 45 15 27 37 14 37 21 16 3 55 24 0 0 15 2 29 2 54 28 63 85 -21 14 55 31 15 9 26 14 19 1 15 45 49 25 0 0 14 43 43 2 54 34 64 84 -20 14 36 44 14 50 41 14 0 8 15 27 10 26 0 0 14 24 22 2 54 40 65 83 -19 14 17 23 14 31 22 13 40 41 15 7 57 27 0 0 14 4 28 2 54 46 66 83 -18 13 57 28 14 11 29 13 20 39 14 48 10 28 0 0 13 44 1 2 54 53 67 82 -16 13 36 59 13 51 3 13 0 4 14 27 50 29 0 0 13 22 59 2 54 59 68 81 -15 13 15 56 13 30 2 12 38 55 14 6 56 30 0 0 13 1 24 2 55 5 69 80 -14 12 54 20 13 8 29 12 17 12 13 45 29 31 0 0 12 39 16 2 55 12 70 79 -13 12 32 10 12 46 21 11 54 56 13 23 28 32 0 0 12 16 34 2 55 19 71 77 -12 12 9 27 12 23 41 11 32 6 13 0 54 33 0 0 11 53 18 2 55 25 72 76 -11 11 46 10 12 0 27 11 8 43 12 37 47 34 0 0 11 29 30 2 55 32 72 74 -10 11 22 21 11 36 40 10 44 46 12 14 7 35 0 0 11 5 9 2 55 39 73 72 -9 10 57 58 11 12 20 10 20 17 11 49 54 36 0 0 10 40 15 2 55 45 74 70 -8 10 33 3 10 47 27 9 55 14 11 25 8 37 0 0 10 14 49 2 55 52 75 67 -7 10 7 35 10 22 2 9 29 40 10 59 50 38 0 0 9 48 50 2 55 59 76 64 -6 9 41 35 9 56 5 9 3 33 10 34 0 39 0 0 9 22 20 2 56 6 76 61 -5 9 15 4 9 29 36 8 36 54 10 7 38 40 0 0 8 55 18 2 56 13 77 57 -4 8 48 0 9 2 35 8 9 44 9 40 44 41 0 0 8 27 45 2 56 20 78 53 -3 8 20 26 8 35 3 7 42 2 9 13 19 42 0 0 7 59 41 2 56 28 78 49 -2 7 52 20 8 7 1 7 13 50 8 45 24 43 0 0 7 31 6 2 56 35 78 44 0 7 23 45 7 38 28 6 45 7 8 16 58 Uncertainty in time = +/- 4 secs Prediction of 2012 Jul 10.0 Data for the target star ------------------------ * name: HIP 41900 * constellation : Cancer * J2000 position with proper motion to date of event [h,m,s ; °,',"] RA: 08 32 38.2325 DE: +15 44 21.948 * position source: mpos:FK6 LTP pm:FK6 LTP plx:FK6 vrad:FK6 * standard error: RA,DE ["]: ( .020, .022 ) * V mag [mag]: 8.0 * B mag [mag]: 9.0 * Apparent position with proper motion RA(deg): 128.3423981628 DE(deg): 15.6937353952 * Equation of equinoxes (radians) : 0.000060407965310 * Diameter [mas]: 0 * remarks: Data for the minor planet ------------------------- * general information: (number) name: (840) Zenobia approx. diameter [km]: 24 approx. diameter ["]: .010 distance from Earth [AU]: 3.39000 * orbital information: orbit source: Preston date of fit: 2012 Jul 10 source of used astrometry: FASTT MPC (via Astdys) number of used observations: 1178 number of rejected observations: 33 time covered by the observations: 1916 Sep 25 - 2012 Apr 01 1 sigma uncertainty ellipse (major, minor, PA): 0.020, 0.014, 113° remarks: * orbital elements for (840) Zenobia : Mean anomaly = 188.13572622 deg Arg. of pericenter = 10.54444389 deg Long. of node = 272.78062333 deg Inclination = 9.98582114 deg Eccentricity = 0.09839401 Semimajor axis = 3.13188630 AU Perihelion dist = 2.82372744 AU Mag: H = 9.98, G = 0.15 Epoch of elements : MJD 56224.12300000 TDT (2012 Oct 24.123) ------ occelmnt file for Occult BEGIN ----------------------------------- 2012 Oct 24 840 Zenobia 2h 56.9m UT 8.0 8 32 38.233 15 44 21.95HIP 41900 9.0 15.5 24 1.4 3.390 1.570 -11.59 51.0033 15.743 131.82 -11.86 2.9489 -0.09109 -0.16664 8.73797 -4.46624 -0.00573 0.00142 2000 187.40255020121020.00000 10.544444272.780623 9.9858210.09839401 3.1318863 2.8237274 9.3 5.00.15 RATE 1.7782590 0.000000 0.000000 0.000000 0.0000000 0.0000000 0.0000000 Meas 0.028 0.026 101 3.62 0.026 0 0-5-2 056118.0020121024__41900 ------ occelmnt file for Occult END ----------------------------------- ============================================ Calculator (s): Steve Preston Date of update: 2012 Sep 03, 19:41 UT Steve Preston 7640 NE 32nd St Medina, WA 98039 425-688-9965 mailto: stevepr@acm.org